Differences in predominant energy substrate in relation to the resected hepatic mass in the phase immediately after hepatectomy.

Changes in the energy substrate utilized by the remnant liver after hepatectomy were studied in relation to the hepatic energy status in 25%, 70%, and 93% hepatectomized rabbits. In 25% hepatectomized rabbits, the energy charge ((ATP + 1/2ADP)/(ATP + ADP + AMP)) level of the remnant liver remained unchanged after hepatectomy and was not affected by portal infusion of (+)-octanoylcarnitine, an inhibitor of fatty acid oxidation. In contrast, the energy charge level of the remnant liver decreased rapidly after 70% hepatectomy and reached the lowest level of 0.77 at 12 to 24 hr after hepatectomy (p less than 0.01). At this time, the energy charge level was further decreased to 0.45 by (+)-octanoylcarnitine (p less than 0.001). It returned to near normal 4 days later. At this time, the effect of (+)-octanoylcarnitine was less evident, with the restoration of the energy change. In 93% hepatectomized rabbits, the energy charge level of the remnant liver decreased rapidly and steeply in the phase immediately after hepatectomy. It is suggested that the remnant liver metabolism switches to predominant utilization of fatty acid as an energy source when the energy charge decreases; it then becomes able to utilize glucose with the restoration of energy charge level. In addition, it is emphasized that hyperosmolar glucose solution or insulin administration during the early period after major hepatectomy should be reconsidered because of their inhibition of the mobilization of free fatty acid from adipose tissue.